Seventy years back in the early days of motor racing, racing cars were driven to the tracks by the drivers themselves (in the absence of any idea of a carrier). Be it to the Le Mans or Targa Florio or even the Mille Miglia, the situation remained the same - the cars had to be driven by team members to the race tracks. 

But with the introduction of more faster cars that came equipped with more instruments that needed highly specialized equipments and manpower (to monitor), need was felt to have one vehicle that could transport all at the same time, to the racing venue. 

One that was used by BMW to move their cars was this Mercedes Benz O317 transporter. A symbolic transporter as both raced their cars against each other.